A persistent problem common to virtually all petroleum products and petroleum-related products is their tendency to undergo oxidative degradation. Oxidation may occur even under the relatively mild conditions attending storage and transport, and is appreciably accelerated when operating conditions are conducive to oxidation processes, for example, the elevated temperatures experienced by lubricating oil. Such oxidative processes not only cause chemical degradation of the petroleum or petroleum-related product, but may also cause appreciable changes in desirable physical properties, such as viscosity, which lead to a deterioration of product performance characteristics. Additionally, the oxidative products themselves may attack materials in contact with the petroleum and petroleum-related products, such as metals in contact with transmission or lubricating oils, thereby causing inefficient performance and, in extreme cases, even mechanical failure.
It has been found that certain N,N',N"-trisubstituted derivatives of bis-(p-aminobenzyl)anilines are effective antioxidants in the aforementioned products at relatively low levels. The materials have the further advantage of admitting to structural variations within broad, but nonetheless well defined, limits thereby permitting optimization of antioxidant properties for a particular product in a specified use.